The rapid spread of fire through the upper floors of a hotel and apartment block building in Dublin poses "serious questions", a local politician has said.
More than 60 firefighters from eight crews were needed to battle the major blaze at the complex in Ballymun near Dublin Airport which broke out on Wednesday night.
Dublin Fire Brigade (DFB) said crews were remaining at the scene into Thursday morning to ensure the fire was completely extinguished.
Images showed that parts of the complex, the upper floors of which are residential apartments, were charred and blackened.
There were no reports of injuries or missing people from the building, which is sometimes used to accommodate families in housing need.
Local Fianna Fail councillor Paul McAuliffe said the blaze was "one of the most significant fires in the Dublin area in recent times".
"Its cause and the spread of it in such a rapid way are going to have to be investigated," he told the Press Association.
"Dublin Fire Brigade have that capacity to investigate these fires. We want to see the results of it and I imagine there will be serious questions asked."
DFB announced on Twitter at around 9.45pm that it was attending a fire at an address in Ballymun.
Witness Anthony Flynn, a co-founder of the Inner City Helping Homeless organisation, said the fire seemed to spread "like mad" in scenes reminiscent of the Grenfell Tower tragedy.
Erica Fleming, whose apartment overlooks the hotel, said she could see and hear windows exploding as a result of the heat.
Ireland's Housing minister Eoghan Murphy tweeted that he was "monitoring the situation closely".
Dublin West TD Roisin Shortall praised the fire services on Twitter for their "excellent and brave work".
The Metro Hotel building comprises hotel rooms on the lower floors and residential apartments on the upper floors.